Question 1. What Is An Isolator And Why Is It Used In The Power System?
An isolator is a disconnecting transfer being operated underneath the condition of on load or negligible contemporary. It is used in the electricity gadget for disconnecting the circuit breaker from the circuit on the time of repair and renovation paintings.
Question 2. Why Are Isolators Provided On Both Sides Of The Circuit Breakers?
Isolators are furnished on each facets of the circuit breakers for repairing work or alternative of breaker with none hazard from the live circuit.
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Question 3. What Interlocking Arrangements Are Generally Provided In The Isolators?
Interlocking with circuit breaker is that the isolator can not be opened until the circuit breaker is opened.
The 3 poles of the isolator must be interlocked for simultaneous operation.
Question 4. What Are The Types Of O.H. Isolators Generally Used?
The kinds of isolators are as follows:-
Vertical ruin kind unmarried, double or triple pole isolator consisting particularly of fixed dirty middle kind insulator help with rigid contacts and moving copper blade supported with the aid of running rod insulator. These are commonly utilized in traction gadget of about 25 kV.
Horizontal rotating put up, middle damage kind isolator consisting of insulator stacks of put up kind insulator established on a bearing and additionally rotatable approximately its vertical axis through ninety°. In this type one insulator stack swings in clockwise course and different in opposite path in this kind of way that the contact arms swings in horizontal plane setting apart at the center. This is used on the voltage upto 220 kV.
Horizontal destroy middle rotating double ruin isolator including 3 insulator stacks consistent with pole having insulator stacks constant on aspects and center insulator stack rotating. Fixed contacts are mounted on the pinnacle of each of the insulator stacks on the facet. It may be utilized in case of all outdoor isolation of circuit breaker, transformer banks, and lightning arrestors and also for line sectionalization.
Extra high voltage column isolator which include a component pantograph on the pinnacle, revolving force insulator, strong center kind porcelain insulator performing as the principle helping unit, the operating cubical furnished with all vital auxiliary contacts & other contacts for supervision & control and a vertically erected metal tube assist anchored to the concrete plinth.
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Question 5. What Are The Advantages Of Extra High Voltage Column Isolators?
The advantages are as follows:-
It requires much less ground region.
It is actually seen from a exquisite distance.
Keeping the fixed contacts alive the transferring contacts may be inspected safely.
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Question 6. What Material Is Used For Making Pantograph Bar & Why?
An aluminium magnesium alloy is used for making pantograph bar for its high mechanical energy, light weight, precise conductivity and more flexibility because of its high elasticity characteristics.
Question 7. In Which Arrangement Of Bus Bar The Bus Coupler Is Very Essential?
Main and switch bus association.
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Question 8. What Is Meant By Insulation Co-ordination?
Insulation co-ordination manner the mutual relation among the insulation of the equipments and the overvoltage characteristics of the protecting tool the idea of which is that the resist overvoltage characteristics of all of the equipments need to lie above the spar over traits of surge arrestor on worst on worst feasible atmospheric condition.
Question nine. What Is The Difference Between An Isolator And A Circuit Breaker?
The distinction between an isolator and a circuit breaker is that, an isolator is a mechanical device able to beginning or closing a circuit without any arc manipulate tool underneath situations of no load or negligible current but a circuit breaker is a mechanical tool for making and breaking a circuit with are manipulate device underneath ordinary and peculiar situations i.E. Even when a heavy fault cutting-edge is flowing.
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Question 10. Why Is An Isolator Installed?
To isolate one part of the circuit from some other.
Question eleven. The Isolators Used In The Transmission Lines Are Capable Of Breaking?
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Question 12. For Which Among The Following The Current Ratings Are Not Required?
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Question 13. Why Are The Isolators Used?
Breaking the circuit under no load situation.
Question 14. It Is A Passive Device Which Allows The Flow Of Optical Signal Power In Only One Direction And Preventing Reflections In The Backward Direction?
Ideally, an optical isolator transmits the signal power in the favored forward path. Material imperfections within the isolator medium generate backward reflections. Optical isolators can be implemented via using FBG.
Question 15. How Many Implementation Methods Are Available For Optical Isolators?
Optical isolators may be implemented using three strategies.
These are as follows:
By using FBGs.
By the use of magnetic oxide materials.
By using semiconductor optical amplifiers (SOAs).
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Question sixteen. A Very Common Application Of Isolator Is To Provide Isolation Between A Low Power Source And The Load?
Isolators have a huge form of packages. The most not unusual among them is the use of an isolator between a high-energy supply and a load to prevent the feasible reflections from unfavorable the supply. An isolator may be utilized in area of a matching network, however it must be found out that any energy pondered from the source is absorbed with the aid of the isolator.
Question 17. Forward Attenuation Provided By A Resonance Fer Rite Isolator Is?
Zero forward attenuation can not be obtained in resonance isolators because the inner magnetic area is not absolutely circularly polarized. Because of this, there is some quantity of ahead attenuation within the isolator.
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Question 18. An Isolator Has A Very Large Operating Bandwidth And Independent Of Any Isolator Parameter?
The bandwidth of an isolator is noticeably slim, dictated basically through the line width ?H of the ferrite material.
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Question 19. The Length Of A Fer Rite Slab Required Operating With A Minimum Forward Insertion Loss And 30 Db Reverse Attenuation And The Reverse Attenuation At This Point Is?
Length of the ferrite slab required is equal to the ratio of the minimum ahead insertion loss to the reverse attenuation at the point. Substituting the given values inside the above equation, duration of the ferrite slab is 2.Four cm.
Question 20. The Electric Field Distribution Of The Forward And Reverse Waves In A Fer Rite Slab-loaded Wave Guide Is Quite Different. This Property Is Used In?
In a discipline displacement isolator, electric powered area distribution of the forward and reverse waves in a ferrite slab-loaded waveguide is exceptional. The electric powered field for the forward wave may be made to disappear at the aspect of the ferrite slab.
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Question 21. Field Displacement Isolators Require Higher Bias Field Than Resonance Isolators?
Field displacement isolators have a whole lot smaller bias discipline requirement since it operates nicely beneath gyro magnetic resonance. This property of area displacement isolator make it extra preferred than resonance isolators.
Question 22. Why Should I Use Isolators?
Isolators provide many benefits that save time and money.
Installation Savings – Machines are hooked up quicker and simpler than anchoring.
Case Histories have proven that the precision leveling and alignment features of Micro/Level® Isolators reduces machine put on and tear; will increase tool existence; and increases productiveness by using reducing downtime and improving part high-quality and repeatability.
Reduce vibration and shock stages for a higher paintings surroundings.
Re leveling and moving the system is also a great deal faster and simpler.
Question 23. How Are Vibro/dynamics Isolators Different From Others On The Market?
Vibro/Dynamics doesn’t use a “one size fits all” method to isolator selection. Every Micro/Level Isolator length has a extensive variety of different elastomeric inserts to exactly meet the isolator characteristics required to remedy a specific trouble.
Our layout is specific. Look at a cross-phase drawing of a Vibro/Dynamics Micro/Level® Isolator. Its design is in contrast to some thing available on the market. Notice that the isolator has pins or “palms” that extend down from the assist housing, bypass through the bearing plate, after which match into “grippers” molded right into a custom-engineered elastomeric. This function, called “Glide/Damping™”, reduces the isolator’s horizontal stiffness and presents a extra diploma of isolation. It also allows hold machines from taking walks by using decoupling the help housing from the elastomeric.
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Question 24. Why Don’t Presses “stroll” On Isolators?
Presses don’t walk on properly selected free-status isolators because of friction among the isolator and the foundation. To maintain a gadget from walking, the static deflection (compression) of the isolator under load should be greater than any dynamic unloading of the isolator caused by the operation of the device. Properly decided on and applied isolators continually convey load, so the friction of the elastomeric at the floor is typically sufficient to triumph over any horizontal forces that purpose a device to walk.
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Question 25. My Press Is Rocking. Is This Normal?
Yes, to an quantity. A press with an unbalanced crankshaft or eccentric will generate a rocking force. Isolators compress and shear in response to those forces, so it's miles normal that a press will rock to some degree. The softer the isolator is, the greater the click will rock. Depending on the clicking and isolators, one-sector inch at the crown isn't always uncommon. The human eye has a tendency to magnify movement, so what looks like excessive movement might not be.
Question 26. How Long Will Isolators Last?
It isn't unusual for Vibro/Dynamics Isolators to closing 30 years or more. When well applied and hooked up, the isolators can last the existence of a system.
Chemicals may be harmful. Vibro/Dynamics has three alternate elastomeric compounds to deal with most environments. Consult with us in case your isolator set up will be subjected to a excessive diploma of chemical publicity.
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Question 27. Why Are You Recommending A Larger Isolator Than Your Competitor?
It can be due to reasons. One, Vibro/Dynamics manufactures vibration isolators as opposed to easy equipment mounts. Our goal is to provide the quality isolation possible while keeping machinery movement to a suitable degree. A large location isolator is mostly a softer isolator. Due to the bigger place, greater isolator deflection is possible without over stressing the isolator’s elastomeric element. Overstressing causes leveling instability (because of elastomeric creep) and the better stress on the foundation.
Two, a larger isolator may additionally have been recommended to offer better aid coverage of the device foot. The isolator support housing have to span the foot gussets.
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Question 28. Why Does The Isolator Stick Out From Under The Machine Foot? Is This A Problem?
The guide housing of a Micro/Level® Isolator is designed to transfer the load on the isolator’s aid housing to the leveling adjustment screw, which then distributes the burden uniformly over a heavy-responsibility metallic bearing plate. The isolator has a built-in swiveling functionality that robotically compensates while the lowest of the device foot is not parallel to the ground, assuring that the isolator’s elastomeric is uniformly loaded.
Most machines have foot and leg designs robust sufficient to permit them to be supported on the mounting hole. Of direction, there are exceptions and the Applications Engineering Staff at Vibro/Dynamics can offer help on this regard. Vibro/Dynamics has a complete line of vibration isolators designed for nearly each state of affairs. If the gadget cannot be supported on the mounting hole, then Vibro/Dynamics will endorse a wedge-style isolator that may be positioned everywhere below the gadget foot.
Question 29. How Do Isolators Reduce Noise?
Isolators are very powerful at decreasing structural-borne noise caused by transmitted vibration. Vibration reasons noise while it excites the herbal frequencies of a structure. This “sounding board” effect is immediately associated with vibration within the assisting floor. Since isolators lessen vibration, structural-borne noise is reduced.
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Question 30. Is It Ok To Use Isolators On A Press With A Rolling Bolster Or Die Cart?
Absolutely. This could be very common. The alignment tolerance for maximum rolling bolster and die carts is enough in order that it is not a trouble.
Question 31. What Is The Allowable Temperature Range For Your Elastomeric Products?
Allowable temperature variety for an elastomeric: zero°F to a hundred°F (-18°C to 38°C) with brief publicity as much as a hundred and fifty°F (66°F).
Question 32. Where Does The Vibration Go When I Mount My Press On Isolators?
Internal forces resulting from the stamping operation arise whether the press is bolted to a basis or installed on isolators. However, the value of the vibration within the press is lower when using vibration isolators.
It is a not unusual false impression that bolting a press to a basis somehow “sucks” the vibration out. Bolting a press to a basis surely topics it to greater vibration and effect pressure. Vibration isolators are cushions that transform a surprising surprise pulse into a decaying collection of longer period forces.
Imagine hitting a brick wall with your fist. It would hurt! Now imagine hitting the wall with the same electricity, however along with your hand in a well padded boxing glove. It hurt much less! Why? It’s due to the fact the impact duration is longer, successfully decreasing the effect force. Short length affects mean higher force.
This is the identical component that occurs on a hard-set up press. The sudden launch of potential strength at snap-via reasons the press foot to slam towards the foundation. This fast period, excessive value pressure hits the foundation and the inspiration responds in kind, sending unfavorable forces returned into the press.
Question 33. Why Do I Still Feel Vibration In The Floor When My Press Is On Your Isolators?
Vibro/Dynamics quotes isolation effectiveness as a percent as compared to the tiers that could exist if the device were anchored or “hard established”. It is not possible to achieve a hundred% with a passive isolation system, but you can come close.
When deciding on isolators, many factors are taken into consideration. But it generally comes down to two troubles: How a great deal isolation is needed and what kind of movement can be tolerated? Isolators are normally decided on to acquire the best quantity of vibration isolation feasible at the same time as maintaining motion to an appropriate level. These are conflicting dreams. To lessen machine motion, the stiffness of the isolator is regularly extended, at the detriment of isolation, ensuing in a few vibration being felt inside the floor.
Inertia Force, that's the pressure generated by way of the motion of the press slide, is another feasible reason of last vibration within the floor. Run the click without material to look if inertia is the motive of the vibration. If vibration is felt, then inertia is contributing to the vibration within the ground.
Elastomeric isolators are not normally designed to isolate inertia force. These are high-tuned isolators, which imply the isolator’s herbal frequency is better than the working pace (SPM) of the press, ensuing in no inertia pressure isolation. In order to isolate inertia force, the herbal frequency of the isolator must be lower than the running velocity of the clicking. Vibro/Dynamics VS Series Spring Isolators have natural frequencies as low as 2.5 Hz., which is ideal for machines jogging over 250 SPM. Added weight is usually required to keep press movement to a suitable degree.
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Question 34. What Can I Do To Reduce The Vibration In My Press?
Vibro/Dynamics isolators have been set up on tens of lots of presses. We have quite a few experience isolating machines with a huge range of various press designs, jobs, and soil conditions. Lowering the surprise level within the device will enhance tooling and system existence and could in addition improve the paintings environment with less vibration inside the plant.
The following list of pointers will assist reduce vibration and keep lots of downtime and cash.
Increase shear in the dies, flat punches will deliver very high snap-via hundreds.
Use an as it should be sized press for the process. Most press producers do now not design their machines to house overloads. For long existence, it's miles recommended to allow a few protection factor in the activity tonnage. A tough or thick batch of metallic or horrific tooling can create an overload, inflicting damage to the system and better vibration stages.
Avoid small dies in machines with a huge die space. Sometimes it has to be completed, however small dies tend to load up and save strength by deflecting the slide like a bow.
For High-Speed blanking in eccentric geared presses, Vibro/Dynamics has observed that 500 ton and higher potential eccentric geared presses strolling faster than 30 SPM generally tend to generate tons greater surprise. For those cases, coil spring isolators are strongly encouraged.
Set the air counter-balance properly.
Make positive the clicking is level and now not twisted.
Reduce the transferring weight or speed. As press pace increases, so does inertia. In some instances, the reciprocating mass of the slide and top die can generate sufficient pressure that it begins to approach the burden of a press, causing the clicking to “stroll”. The components for figuring out the “inertia pressure” generated by using the slide and upper die is: inertia force (Peak-Peak)= W/g*r*ω2 wherein W=transferring weight, g=acceleration of gravity (nine.8 m/s2 or 386 in/s2), r=stroke length, and ω=system operating speed in rads/sec (1 SPM = 0.A hundred and five rad/sec). Note that the gadget velocity is a dominant term, doubling the speed quadruples the inertia pressure.
To test for an inertia pressure vibration hassle, run the gadget with out hitting material at the velocity that typically causes problems. If the vibration trouble persists, then the inertia pressure generated through the unbalanced moving mass is the motive of the vibration.
Some gadget developers lessen the generated inertia forces in their speedy jogging machines through the use of a “dynamic balancer”, a slide that runs 180° out-of-section (at once contrary) from the main slide and top die. The dynamic balancer is often one hundred% balanced for a “regular” higher die weight, however can be constrained due to clearances within the press crown structure. Spring isolators may be used to install most dynamically balanced presses, but a movement analysis over the clicking’ speed range have to be executed first.
Make sure the tie rods are stretched successfully.
Make positive there aren't any “quick circuits.” Avoid beams, deck plates, and feeds which can be related to both the click and the muse.
Check and hold press level.
Question 35. My Machine Is Installed And The Vibrations Are Interfering With Nearby Offices Or Sensitive Equipment, What Can I Do To Fix This?
Once machines are hooked up and a vibration trouble is discovered, it is often very difficult and high-priced to relocate the offending gadget or sensitive location. Surface vibration waves are generally the perpetrator. The amplitude, or severity, of surface waves decreases through a feature of as a minimum (1/distance from vibration supply)0.Five. High frequency waves will use up over shorter distances than longer wavelength, low frequency waves. Vibration waves are further attenuated by using damping losses function of the substances they are traveling within. Steel, concrete, and frozen water/soil is green conductors of vibration. Surface waves can hence travel sizeable distance and nevertheless cause issues. It is only to lessen the amplitude of the waves at the supply and on the touchy region. The maximum value green manner to reap isolation of the vibration waves is by way of the use of passive vibration isolators.
Many different methods had been employed to try to reduce the surface wave vibrations, with generally confined fulfillment:
Digging trench vibration barriers between the offending system and the touchy place can reduce vibrations degrees by 25% and occasionally extra. Hard boundaries together with concrete are typically useless, although introducing any dissimilar material will bring about some wave reflection. The barrier method may be very luxurious and incredible care must be taken to design the trench. If the ditch is simply too shallow, the surface waves may additionally skip under it. If the trench does no longer absolutely encircle the supply, the vibrations can also bend and replicate and pass the barrier on the edges. There may be a shadow area in the back of the trench in which the vibration waves are reduced. Trenches will also be useless if the offending vibrations are compression waves reflecting from deep rock. Trench boundaries will reflect a few waves lower back towards the supply resulting in expanded vibration tiers around the offending gadget.
Replacing conductive soil or structures with greater pretty damped or extra bendy connections at choppy periods can reduce vibration transmission. This technique is now not unusual in pipe runs from vibration producing gadget inside constructing systems. Within business plant life these measures are usually impractical and the vibration discount generally small.
Separating the muse from the surrounding soil and making the guide vicinity of the muse as deep as possible will reduce surface waves. Like trench obstacles, this method is high-priced and space inefficient. This method works on the principle that surface waves do not travel effectively at intensity.
Stiffening a vibrating structure this is in resonance can resolve problems in mezzanines and simple systems. A common problem is a multi-story or brief office flooring have low herbal frequency modes that can be excited efficiently by using machinery shocks or, more usually, periodic vibrations. Machines like stamping presses and hammers introduce a high importance surprise into the surroundings that cause a big temporary wave to propagate. Many machines with rotating additives consisting of high speed presses, vibrators, flywheels, mills, and motors can produce constant periodic vibrations. Stiffening the floors of such structures to raise the herbal frequency can alleviate the hassle. Stiffening an existing shape is luxurious due to the fact regularly the stiffness needs to be at the least doubled to acquire important consequences. When the problem is a gadget with a very bendy arm including on CMMs, EDMs, robotic welders or torches, and a few turbines, stiffening the arm may be a simple and effective solution.
Adding weight to the sensitive system is somewhat powerful with diminishing returns as weight is added. Sometimes known as mass loading, this approach increases the inertia of the device. This approach is only whilst employed with passive vibration isolators to create a completely low natural frequency device. In the form of a massive inertia mass with isolators and a sub-foundation, the isolated system is named an remoted foundation.
To avoid highly-priced vibration mitigation measures it's miles high-quality practice to be aware about vibration issues before a device is established. It is essential to understand the frequency content material of the source and the touchy frequencies of the environment.
Question 36. Do I Still Need A Foundation If I Use Machinery Mounts And Isolators?
Isolators do now not eliminate the want for a nicely-designed basis. The foundation have to be strong sufficient to assist the physical weight of the equipment, plus the dynamic forces generated with the aid of the system. Dynamic forces range with machine traits. Well-designed isolators will reduce the dynamic pressure transmitted right into a foundation, however determining the quantity going into a foundation is very tough.
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Question 37. How Much Force Is Transmitted To The Foundation When A Machine Is Installed On Isolators?
In order to determine the transmitted force, the frequency and forces being generated must be known as nicely as the characteristics of the soil, basis, and system construction. Many of the variables influencing the significance of the input forces are not regarded or even measurable.
Factors that strongly influence the transmitted pressure:
Structural response of device to shock
Stamping operation (i.E., blanking, coining, drawing, etc.)
Foundation length and pressure
Estimates of transmitted forces can be made, but they're most effective estimates. Vibration isolators are the most important factor in lowering transmitted vibration. However, the vibration isolators have to be given the proper situations to function at peak performance.
Question 38. Is My Current Foundation Or Floor Sufficient?
They can investigate the neighborhood soil conditions, the repute of the prevailing concrete, and the repute of the present reinforcing metal. Areas with excessive water tables or that have been crammed may want to probably cause problems if the inspiration design does not take them into consideration.
Question 39. How Do I Measure The Foundation Stiffness (okay) And Natural Frequency (fn)?
The soil under the foundation will regularly be compacted at some point of foundation creation after which further loaded and compacted because the installation a long time and machines are run. So the completed installation is regularly very distinct from while the site changed into only a plant floor or an open area. Foundation Natural Frequency (Fn) can be determined via losing a mass and recording the floor vibrations.
Two sorts of tests can be completed via Civil Engineers to decide the soils present at unimproved websites:
The most effective is a penetration take a look at where a pipe is pushed into the floor and the variety of blows and the given distance traveled are recorded. More blows same harder, more compact soil. Core samples are retrieved and inspected to determine the kind of soils gift. The soil is analyzed and a chart of blows and soil kind consistent with depth is commonly furnished.
Another common and fairly simple take a look at is a move-hole size of the soils. Two holes are bored and a transducer is diminished into one and a seismometer inside the different hollow. By measuring the velocity of the waves exceeded among the holes, an estimate of the soil stiffness (elastic modulus) is acquired.
A Red Flag is while the soil is determined to be very terrible with excessive quantity of fine clays and excessive water table. The foundation will generally tend to have a lower herbal frequency and lower bearing capability if the soil is negative. In those cases, Vibro/Dynamics advises a larger foundation and "foot print" with the softest isolators permissible to keep away from settling and to enhance isolator effectiveness. If the muse is under-sized, the isolators will have reduced effectiveness regardless of their stiffness.